The molar vectorinsert ratio in Ligation 1 was 31 Ligation 2

The molar vector/insert ratio in Ligation 1 was 3:1; Ligation 2 was 1:1 and Ligation 3 was 1:2. A number of ligations were done in the hope that one might produce more recombinants than another. Ligation 1 with the 3:1 ratio generated the most recombinants. Why

Solution

I guess there is a writing mistake in the question. It is supposed to be 1:3 not 3:1 because the vector is a bigger molecule with the restriction enzyme treatment having both ends cut. Where on the other end insert is relatively a small molecule when compared to vector. So there has to be a greater number of insert rather than greater number of vector. So if in the ligation 1 there was a ratio of 1:3, it obviously will generate the most recombinants having the highest number of insert.